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make cloned generic over deref... and have its tests actually run

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This commit is contained in:
Alexis Beingessner 2014-11-17 20:59:46 -05:00
parent f09279395b
commit 9702fb9c7b
2 changed files with 27 additions and 10 deletions
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8
src/libcore/option.rs
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@ -153,6 +153,7 @@ use result::{Result, Ok, Err};
use slice; use slice;
use slice::AsSlice; use slice::AsSlice;
use clone::Clone; use clone::Clone;
use ops::Deref;
// Note that this is not a lang item per se, but it has a hidden dependency on // Note that this is not a lang item per se, but it has a hidden dependency on
// `Iterator`, which is one. The compiler assumes that the `next` method of // `Iterator`, which is one. The compiler assumes that the `next` method of
@ -694,11 +695,12 @@ impl<T> Option<T> {
} }
} }
impl<'a, T: Clone> Option<&'a T> { impl<'a, T: Clone, D: Deref<T>> Option<D> {
/// Maps an Option<&T> to an Option<T> by cloning the contents of the Option<&T>. /// Maps an Option<D> to an Option<T> by dereffing and cloning the contents of the Option.
/// Useful for converting an Option<&T> to an Option<T>.
#[unstable = "recently added as part of collections reform"] #[unstable = "recently added as part of collections reform"]
pub fn cloned(self) -> Option<T> { pub fn cloned(self) -> Option<T> {
self.map(|t| t.clone()) self.map(|t| t.deref().clone())
} }
} }

29
src/libcoretest/option.rs
View File

@ -241,14 +241,29 @@ fn test_collect() {
assert!(v == None); assert!(v == None);
} }
#[test]
fn test_cloned() { fn test_cloned() {
let s = 1u32; let val1 = 1u32;
let n: Option<&'static u32> = None; let mut val2 = 2u32;
let o = Some(&s); let val1_ref = &val1;
let opt_none: Option<&'static u32> = None;
let opt_ref = Some(&val1);
let opt_ref_ref = Some(&val1_ref);
let opt_mut_ref = Some(&mut val2);
assert_eq!(o.clone(), Some(&s)); // None works
assert_eq!(o.cloned(), Some(1u32)); assert_eq!(opt_none.clone(), None);
assert_eq!(opt_none.cloned(), None);
assert_eq!(n.clone(), None); // Mutable refs work
assert_eq!(n.cloned(), None); assert_eq!(opt_mut_ref.cloned(), Some(2u32));
// Immutable ref works
assert_eq!(opt_ref.clone(), Some(&val1));
assert_eq!(opt_ref.cloned(), Some(1u32));
// Double Immutable ref works
assert_eq!(opt_ref_ref.clone(), Some(&val1_ref));
assert_eq!(opt_ref_ref.clone().cloned(), Some(&val1));
assert_eq!(opt_ref_ref.cloned().cloned(), Some(1u32));
} }